1. **Problem:** Points B, D, and E lie on a circle. ABC is the tangent to the circle at B. Find the size of angle EDB. 2. **Formula and rules:** The angle between a tangent and a chord through the point of contact equals the angle in the alternate segment. 3. **Step 1:** Since ABC is tangent at B, angle ABC equals angle EDB (alternate segment theorem). 4. **Step 2:** Angle ABC is given or can be found from the diagram (assumed known or calculated). 5. **Step 3:** Therefore, angle EDB = angle ABC. 6. **Reason:** By the alternate segment theorem, the angle between tangent and chord equals the angle in the alternate segment. Final answer: angle EDB = angle ABC (value depends on given data).